Changes in microcirculation of the trapezius muscle during a prolonged computer task.

The aim of this study is to investigate if there is a change in oxygen saturation and blood flow in the different parts of the trapezius muscle in office workers with and without trapezius myalgia during a standardized computer task. Twenty right-handed office workers participated; ten were recruited based on pain in the trapezius and ten as matching controls. Subjects performed a combination of typing and mousing tasks for 60 min at a standardized workstation. Muscle tissue oxygenation and blood flow data were collected from the upper trapezius (UT), the middle trapezius (MT) and the lower trapezius (LT), both on the left and right side at seven moments (at baseline and every tenth minute during the 1-h typing task) by use of the oxygen to see device. In all three parts of the trapezius muscle, the oxygen saturation and blood flow decreased significantly over time in a similar pattern (p < 0.001). Oxygenation of the left and right UT was significantly higher compared to the other muscle parts (p < 0.001). Oxygen saturation for the MT was significantly lower in the cases compared to the control group (p = 0.027). Blood flow of the UT on the right side was significantly lower than the blood flow on the left side (p = 0.026). The main finding of this study was that 1 h of combined workstation tasks resulted in decreased oxygen saturation and blood flow in all three parts of the trapezius muscle. Future research should focus on the influence of intervention strategies on these parameters.